[GTALUG] War story: OpenWRT USB access

Giles Orr gilesorr at gmail.com
Sat Jan 10 19:48:47 UTC 2015

On 7 January 2015 at 22:20, Scott Sullivan <scott at ss.org> wrote:
> On 01/07/2015 01:52 PM, D. Hugh Redelmeier wrote:
>> | From: Giles Orr <gilesorr at gmail.com>
>> | I'm willing to try anything by this point, so I installed:
>> |
>> | kmod-nls-iso8859-1
>> | kmod-nls-cp437
>> |
>> | Test again, and ... I can mount USB storage devices!
>> Wow.
>> I wonder how you could have figured this out (except via folklore).
>> Since it is a kernel module that is missing the nls-* modules, the
>> only ways of reporting the problem are: EWHATEVER return code (rather
>> non-specific) or logging (would have to be rate-limited).  I guess
>> neither of these were used.
>> Can you fix the web page that gave you the first hints to include the
>> lore about nls-*?
> I remember going through this very same series of events as Giles. It was a
> few years ago with the TP-Link MR-3020, which I was setting up as a portable
> PXE boot server.
> I was going through various parts of the wiki on that, but found the need
> information was covered in comprehensive document. Ah yes, this looks to be
> the one.
> http://wiki.openwrt.org/doc/howto/storage
> Also relevant, but assumes ext a linux-ish file systems, so doesn't mention
> VFAT or it's NLS needs.
> http://wiki.openwrt.org/doc/howto/usb.storage

I wanted to confirm Scott's implied thesis, so I installed and
uninstalled packages to do a few tests: the NLS files are required for
vfat filesystems, but NOT for ext4 or iso9660 filesystems.  So an
appropriate kmod-nls-* should be a dependency for the kmod-fs-vfat
package but not for USB storage in general.  But I don't think (didn't
research this part) opkg supports virtual dependencies, and forcing a
download of all NLS packages wouldn't work ...  Okay, it _might_ work,
but these are low-resource devices: it might also exhaust all space on
the storage media.  So it's a pretty thorny problem.

gilesorr at gmail.com

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